Input of selected human pharmaceutical metabolites into the Norwegian aquatic environment

The occurrence of the metabolites of five human pharmaceuticals was investigated in treated wastewater, surface waters and sediments. Metabolites of carbamazepine (carbamazepine epoxide), diclofenac (4'- and 5-hydroxy diclofenac) and atorvastatin (o- and p-hydroxy atorvastatin) were typically detected in flow proportional 24 h composite samples of wastewater effluent collected from the Norwegian cities of Oslo and Tromso at higher concentrations than the parent pharmaceutical. The concentrations determined in discharged effluent were as high as 3700 ng L-1 for 5-hydroxy diclofenac. The overall mean concentration of metabolites being typically higher in the primary treated effluent from the city of Tromso compared to the tertiary treatment performed on the Oslo effluent. Metabolites of carbamazepine (carbamazepine-10,11-epoxide), metoprolol (alpha-hydroxy metoprolol) and simvastatin (hydroxy simvastatin) were detected in surface water samples collected from Oslofjord at concentrations of up to 108 ng L-1, whilst alpha-hydroxy metoprolol and simvastatin hydroxy carboxylic acid were also detected in sediments at low ng L-1 concentrations. These screening data show that the metabolites of selected pharmaceuticals are being discharged into the Norwegian coastal environment and that certain metabolites occur in marine surface waters and sediments.